Mosquito season in Herkimer County, NY: when it starts and ends
Mosquito months in Herkimer County
In a normal year mosquito season in Herkimer County, NY starts around May 8 and ends around October 4, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Herkimer County, and when
- Start tipping out standing water weekly by April 24.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 4.
- No West Nile cases since 2016, so bites in Herkimer County are a nuisance; check window screens.
Herkimer County against the rest of NY
Herkimer County has the 58th longest season of 62 NY counties, at 149 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 42°F.
- Allegany County: May 8 to October 9 (154 days, 0 WNV)
- Greene County: May 7 to October 6 (151 days, 3 WNV)
- Hamilton County: May 9 to October 3 (147 days, 0 WNV)
- Fulton County: May 10 to October 1 (145 days, 0 WNV)
West Nile in Herkimer County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Herkimer County (0 neuroinvasive) across 1 year. The worst was 2003 with 1; the latest was 2003.
Background: when mosquitoes go away for the winter; how the dates are worked out.